/****************************************************************************
 * fs/mount/fs_umount.c
 *
 *   Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
 *   Copyright (c) <2014-2015>, <Huawei Technologies Co., Ltd>
 *   All rights reserved.
 *
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/
/****************************************************************************
 * Notice of Export Control Law
 * ===============================================
 * Huawei LiteOS may be subject to applicable export control laws and regulations,
 * which might include those applicable to Huawei LiteOS of U.S. and the country in
 * which you are located.
 * Import, export and usage of Huawei LiteOS in any manner by you shall be in
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 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include "vfs_config.h"

#include "sys/mount.h"
#include "errno.h"
#include "fs/fs.h"

#include "inode/inode.h"
#include "stdlib.h"

#include "string.h"
#include "disk.h"

extern int close_files(struct inode *inode);
#ifdef VFS_USING_WORKDIR
extern char working_directory[PATH_MAX];
#endif

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Public Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: umount
 *
 * Description:
 *   umount() detaches the filesystem mounted at the path specified by
 *  'target.'
 *
 * Return:
 *   Zero is returned on success; -1 is returned on an error and errno is
 *   set appropriately:
 *
 *   EACCES A component of a path was not searchable or mounting a read-only
 *      filesystem was attempted without giving the MS_RDONLY flag.
 *   EBUSY The target could not be unmounted because it is busy.
 *   EFAULT The pointer argument points outside the user address space.
 *
 ****************************************************************************/

  int umount(const char *target)
  {
    FAR struct inode *mountpt_inode = (struct inode *)NULL;
    FAR struct inode *blkdrvr_inode = (struct inode *)NULL;
    int errcode = OK;
    int status;
    char *fullpath = (char*)NULL;
    char *relpath = (char*)NULL;

    /* Verify required pointer arguments */

    if (!target)
    {
        errcode = EFAULT;
        goto errout;
    }

    /* Get a absolute path*/
    errcode = vfs_normalize_path((const char *)NULL, target, &fullpath);
    if(errcode < 0)
    {
        errcode = -errcode;
        goto errout;
    }


    /* Find the mountpt */

    mountpt_inode = inode_find(fullpath, (const char **)&relpath);
    if (!mountpt_inode)
    {
        errcode = ENOENT;
        free((char *)fullpath);
        goto errout;
    }

    /* Verify that the inode is a mountpoint */

    if (!INODE_IS_MOUNTPT(mountpt_inode))
    {
        errcode = EINVAL;
        goto errout_with_mountpt;
    }

    /* Verfy the path is a mountpoint path or file path*/
    if (relpath && strlen(relpath))
    {
        errcode = EPERM;
        goto errout_with_mountpt;
    }

    /* Unbind the block driver from the file system (destroying any fs
     * private data.
     */

    if (!mountpt_inode->u.i_mops->unbind)
    {
        /* The filesystem does not support the unbind operation ??? */
        errcode = EINVAL;
        goto errout_with_mountpt;
    }

    inode_semtake(); /* Hold the semaphore through the unbind logic */
    status = mountpt_inode->u.i_mops->unbind( mountpt_inode->i_private, &blkdrvr_inode);
    if (status < 0)
    {
        /* The inode is unhappy with the blkdrvr for some reason */

        errcode = -status;
        goto errout_with_semaphore;
    }
    else if (status > 0)
    {
        errcode = EBUSY;
        goto errout_with_semaphore;
    }

    /* Successfully unbound */
    mountpt_inode->i_private = NULL;
    mountpt_inode->u.i_ops= (const struct file_operations_vfs *)NULL;
    mountpt_inode->i_flags = 0;
#ifdef CONFIG_FILE_MODE
    mountpt_inode->i_mode = 0;
#endif
    inode_release(mountpt_inode);
    /* Successfully unbound, remove the mountpoint inode from
     * the inode tree.  The inode will not be deleted yet because
     * there is still at least reference on it (from the mount)
     */
    inode_semgive();

    /* Did the unbind method return a contained block driver */

    if (blkdrvr_inode)
    {
        blkdrvr_inode->e_status = STAT_UNMOUNTED;
        inode_release(blkdrvr_inode);
    }

    free((char *)fullpath);
    return OK;

    /* A lot of goto's!  But they make the error handling much simpler */

errout_with_semaphore:
    inode_semgive();
errout_with_mountpt:
    mountpt_inode->i_crefs--;
    if (blkdrvr_inode)
    {
        inode_release(blkdrvr_inode);
    }
    free((char *)fullpath);
errout:
    set_errno(errcode);
    return VFS_ERROR;
}
